Why would your girlfriend cheat on you but still want to keep the relationship going?

Short answer: Well you are the judge depending wether the guy she cheats on you look better than you. If she keeps the relationship going 95% of the time, she's still going to cheat again.

If he is on you're level or below wether you want to believe it or not no matter what the excuse is if she really connects with him she would be with him not you. She may have been a little revengeful but she didn't mean it. If the guy looks better than you and connects better than you, you should sit down with both of them, ask them do they see each other in their future, and there's you're answer